Conventionally, a remote user interface (UI) is known as a technique of providing an interface to an apparatus on an operating side when remotely controlling an apparatus connected thereto via a network.
The remote UI is realized by a server apparatus (a remotely controlled apparatus) that transmits a file required for execution of an application and a client apparatus that is connected to the server apparatus via a network and executes the application by using the file received from the server apparatus. Specifically, the client apparatus holds the IP address of the server apparatus and the name of the application that is to be activated. When receiving an instruction to activate the application, the client apparatus requests the server apparatus to transmit the file required for execution of the application (a definition file of a UI or display contents). When receiving the file from the server apparatus, the client apparatus executes the application by using the received file, and displays an operation screen (UI).
As a technique other than the above remote UI, a screen shot technique is known. The screen shot technique is a technique in which a screen shot that is a display image after completion of activation of an application is displayed during a period from start of an activation process of the application to the completion thereof, in order to make the activation speed of the application appear faster. Here, the screen shot is obtained by storing, as a bitmap, a rendered content that is written by the application into a frame buffer (a memory for temporarily storing raster data of an image to be displayed on a display).
Specifically, immediately after the start of the activation of the application, previously prepared data of a screen shot is written into the frame buffer, and the screen shot is displayed on the display. Then, at the time when the activation of the application is completed, the content stored in the frame buffer is replaced with a rendered content generated by the application. Thereafter, display data of the application is displayed on the display. Actually, the display data of the application is not displayed until the activation of the application is completed. In contrast, when a screen shot is displayed immediately after the start of the activation of the application, a user feels that a waiting time to the completion of the activation process is shortened.
Further, as a technique related to display control of an image, there is a technique disclosed in Patent Literature 1. Patent Literature 1 relates to a display control apparatus that generates a display image by combining a plurality of pieces of compressed block data. In Patent Literature 1, when an image that is the same as an image already displayed on a screen is displayed, high-speed image display is implemented by using image data already decompressed on image data storage means.